Transmission itself seems to be moving up and down...
 

Just bought a 2004 manual GT and the guy said something about the trans brace or whatever "might" need new bushings. Yeah...it needs something alright, the shifter raises and drops a good 1.5 inches especially in 1st gear! I have yet to get under the car to look at what's going on but could it be as simple as bushings or do I likely have a bigger problem? I'm surprised that input/output shafts haven't snapped with how much this thing moves.

I would check motor mounts also.

There is no transmission bushing.

Motor on one end, a metal brace (torque tube, Power Plant Frame, Heavy Metal Piece) runs from the trans (4 big bolts) to the diff (5 big bolts). If the shifter is moving up and down, this is lose. drive gently to someplace where you can get it fixed. All you need to do is loosen the bolts, line it up, and tighten the bolts.

Spec is that the PPF is so many inches off the front cross brace, if it has not been bent. I would check this first, then the motor mounts. But, make sure the trans is on a jack before you loosen anything. there are procedures in the shop manual posted here someplace.

If that does not do it, then motor mounts. But to get 1.5" lift, in the center, the motor would have to really be lose.

Is it the tranny or the shifter? If the shifter bushing goes it can get very loose

I can go put the car on a lift tomorrow to get a good look. So the metal brace is what you're saying is loose, or unaligned? Could you elaborate on how it can be unaligned?

In this picture you're referring tot he silver metal scaffolding from the engine to the diff.

https://www.rx8club.com/attachments/...ppf-small-.jpg

I'm pretty sure it is the tranny. However, I won't rule out the shifter bushing since I'm not as familiar with these cars. In normal operation the shifter sits very low in the hole and the back seems to be farther down than the front. The forward gears are easy to get into gear, the rearward gears (2,4,6) seem to want to pop out easily due to the angle. When I accelerate in the lower gears especially, the whole shifter assembly/transmission rises up a ton.

If the whole tranny is moving up and down as much as you say...your motor mounts are toast...even if the PPF is loose I can't see the mounts being OK

You need to check the diff mounts as well..they are rubber and not designed to take the torsion of it being that loose for long

I'll take pics of everything tomorrow.

I am referring to the silver metal scaffold stuff. Although, on mine it is black steel. If the bolts on the trans end are loose, you can rock the tail shaft up and down. The torques from driving the car will move things around. Not sure how, do not want to do the math, but that is the only way I know to move the shifter up and down.

Unless, the busing is completely worn and the shifter can be lifted up and down while sitting still. I would see if you can pull it up and down at rest before getting under the car.

And yes, if the trans is moving this much, it will really put a load on the motor mounts. Once you are sure it is tied down, look to them next. Would not hurt to look at the diff mounts as well, but they cannot really move the trans that much.

Good luck, be safe.

My educated guess is that single rear trans mount. Can't lift the shifter sitting still.

There is no transmission mount. It is the 2 motor mounts and the diff mounts. .. the rest is hard connected with the PPF :-)

Oh...what is this part?

Attachment 287563

That's a MX5 for one. .. but that is a vibration damper :-)

Doh, thanks a lot google. lol

Don't worry, the 8 is similar. My opinion is that the bolts in the where you have the red circle are loose. The torque spec is high, somthing around 110 ft lbs.

The position spec is 2" between the top of the front tunnel brace and the bottom of the horizontal part of PPF. This assumes that the brace is straight. Check that first. If bent, make sure the PPF is not resting on it, pull it off and straighten in (Hammer works). Try not to flatten it. it is not the strongest piece of the car.

You were right, the front area of the brace was missing one of the bottom nuts completely and the other 3 were loose enough to slide. Tightened them up with an impact but forgot to use a torque wrench. So far it's great, no more up and down.

Now I need to find out why 2nd gear wants to pop out and 4th grinds going in.

Well, that is part one.

Next, i would change the fluids in the trans. No idea on second gear, but 4th is likely a lame synchro. Those bolts being lose mean somebody might have already messed with the trans. Put something like red line MT 90 in and see how it goes.

I also suggest getting the correct torque on those bolts....

I have a trans that stays in second gear, but it will also crunch a tad going into 4th if you are really on it. Does pretty well on the street, but is a bit rough at the track.

Oh and one more trans related issue: When I floor it in 1st to redline and go to shift, the clutch stays on the floor until the rpms drop to like 7k. What is going on? That's the only time it does it.

sounds like you have a botched transmission install. maybe from a bad clutch install.

try second gear at that rpm as well. if the stack height for the clutch is off, it will do that, stay depressed at high RPM. search for posts I made on transmission installs. I made most of the possible mistakes. I cannot search from my phone.

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I looked at your threads you've started but didn't see one that applied..

But basically what do I need to look at and change when I drop the transmission to fix this issue?

more time..

the distance from the flywheel to the pressure plate is a big deal and carries through the springs to the little fingers the release bearing press against. those fingers are important. from the mistakes I have made, those need to "crown" about a tenth of an inch. the tips should be about a tenth of an inch father away from the engine than the base. You get them away from the engine by inserting a washer between the flywheel and pressure plate.

if there is no crown, the speed of the engine will start to release the clutch above 7k.

gotta run

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I see, it has a Spec stage 3 clutch in it that I'll probably replace with an OEM.